The rails of a railroad track are sometimes used as electrical conductors that carry electrical signals. For example, track circuits are used to detect the presence or absence of a train on rail tracks. This information can then be used to inform signalers and control relevant signals. In a typical track circuit, power is applied to each rail at one end of a section of track, such as a block. An electrical relay is electrically coupled across the rails at an opposite end of the section of track. When no train is present, the relay is energized by the current flowing through the rails. When a train is present, its wheels and axle electrically short the circuit formed by the rails. This causes the current to the relay to drop, and the relay is de-energized. The state of the relay can therefore be used to indicate whether a train is present on the section of track.
Rail feeds are used to effect an electrical connection between a rail and, for example, a control unit. The rail feed can be used to transmit an electrical signal on, or receive an electrical signal from, the rail. Rail bonds are used to electrically couple longitudinally adjacent lengths of rail, as there is typically a gap between the rail ends.
Various methods are and have been used to implement rail feeds and rail bonds. One method is to mechanically connect an electrical conductor via a hole that is formed in the rail. Such a mechanical connection can take the form of a bolt or a screw, for example. This hole can be formed, for example, by drilling or pounding. This drilling or pounding can cause a flaw in the rail, making the rail more likely to fail or break. Another method is to weld an electrical conductor to the rail. The heating of the rail that is inherent in the welding process can also cause flaws in the rail, again making the rail more likely to fail or break. Other methods include pin brazing and gluing. These methods suffer from their own disadvantages including low reliability. Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.